1. Field of the Invention
The present invention relates to a latch mechanism for securement to the style of a closure element, and particularly, but not exclusively, to a sliding door and capable of achieving high performance resistance against forced entry.
2. Description of Prior Art
The door latch mechanism of the present invention is particularly useful for securement to the style, or for incorporation within the style, of a sliding door, such as a patio door. Various door latch mechanisms are known, such as disclosed in U.S. Pat. No. 4,607,510, for securement to sliding doors, and these are essentially comprised of a slide plate guidingly located in a housing and provided with one or more hook fingers for engagement within a keeper housing. However, some of these door latch mechanisms do not provide adequate resistance to force entry and their resistance performance level is usually within the F1 or F2 range of forced entry tests, as well known in the art. Some of the problems encountered during forced entry include: disconnection of the locking fingers from the keeper member by lifting the door panel or jumping the panel from its support track;, breakage or disconnection of the keeper member by applying a lateral sliding force to the sliding door; breakage or disconnection of the latch plate or keeper; and material failure under load due to poor design and inadequate material strength.